The invention relates to a semiconductor component with interface functions between the controller and the power components of power inverters, suitable for the control of semiconductor components, in particular for the control of IGBT (Insulated Gate Bipolar Transistor) and MOSFET (Metal Oxide Semiconductor Field Effect Transistor) power switches.
Hybrid control circuits are well-known from the state of the art. In xe2x80x9cApplikationsbuch IGBT- und MOSFET- Leistunsmodulexe2x80x9d (Applications Book for IGBT and MOSFET Power Modules (ISBN 3-932633-24-5) as well as in the catalog ""99 of SEMIKRON Electronics GmbH, circuit arrangements of this kind are described for the control of semiconductor power switches. In the following, the problems involved in controlling these elements will be discussed on the basis of block diagrams.
FIG. 1 represents the principal structure of a power electronics system for the control of high voltage IGBTs according to the state of the art. In detail, the power electronics system consists of:
a controller (1) with, e.g., a microprocessor, memory and A/D and/or D/A converter,
a control circuit (2) with digitalxe2x80x94, analogxe2x80x94and power components for signal processing as well as power supply and error processing,
a separation (3) between the low and high voltage parts,
the driver circuit (4) with power supply, gate driver and monitoring elements,
the intermediate circuit (5),
the power switches (6),
a consumer device (7), and
sensors with signal-processing circuits (8).
The connection to the power semiconductor switches is illustrated through a partial representation of an inverter circuit showing two IGBTs of a half bridge, the intermediate circuit of the converter, and the consumer device (symbolically represented by a motor).
Sensors (which may include signal-processing circuits) for all relevant operational variables are used to acquire the characteristic operating variables of the consumer device and of the power switches (e.g. rpm rate, position, torque of the consumer device, and temperature, current, and short-circuit condition of the power switches) and to transmit the values of the variables to the control circuit or the controller to generate the corresponding data for determining the operating state of the converter during its operation.
Semiconductor technologies are now available for low-voltage applications (e.g. applications in batteries, applications in automobiles with intermediate circuit voltages smaller than 100V), so that controller circuits, control- and driver circuits as well as circuits for the separation between potentials and for the acquisition of data characterizing an operating state can to a large extent be monolithically integrated. With higher intermediate circuit voltages, the integration of the separation of potentials (and/or level converter stage) becomes more and more difficult because of isolation problems. At the current state of the art, solutions are available for the integration of level-converter stages up to 600V and recently also up to 1200V. They are described in International Rectifier Data Sheets IR2130 and IR2235. The advantages of these solutions lie in their high degree of integration and the associated cost savings. The drawbacks of these solutions lie in the restricted voltage range and the limited driver power which decreases if voltage range is increased, and in the sensitivity to interference in a rough electromagnetic environment.
Applications possibilities for this technology are limited because of the required bootstrap power supply and the lack of a true galvanic separation, which represents a severe disadvantage of the existing state of the art. For intermediate and high power levels, it is therefore necessary to use additional opto-couplers, transmitters or post-amplifiers.
A monolithic integrated potential separation is made possible only by using dielectric isolation technologies, as for example an auxiliary carrier technology that has been described by C. Y. Lu (IEEE Trans. On E.D. ED 35 (1998), pp. 230-239), by wafer bonding with trench isolation according to K. G. Oppermann and M. Stoisiek (ISPSD 1996, Proc. S. 239-242) and/or by the SIMOX technology according to Vogt et al (ISPSD 1997, Proc. pp. 317-320). These technologies are limited to isolation voltages of less than 1200 V (in most cases less than 600 V) because of the realizable oxide thicknesses of less than 2 xcexcm, and they are furthermore very cost-intensive.
In practice, for voltages above 100V, discrete opto-couplers or transmitters are used for the potential separation between the low and high voltage side. The advantage of transmitters in comparison to opto-couplers lies in the bi-directional data flow for control signals and/or error signals. In addition, a power transmission with a floating potential for the current supply of the high voltage side is possible only with transmitters.
If discrete opto-couplers or transducers are used, it is necessary to use separate, discrete or integrated circuits both on the low and high voltage side. In certain cases (e.g., at low power levels and with few analog functions), a monolithic integration of the functions of the low-voltage side with the controller is possible.
Another possibility according to the state of the art is offered by the hybrid integration circuit of opto-coupler components with an integrated circuit including driver- and monitoring functions (on the high voltage side) in a special housing (Hewlett-Packard Data Sheet HCPL-316, December 1997). In this case, a high degree of integration is realized for high voltages (from 600V to 1200V), as well as suitability for intermediate and high power levels.
The only discrete components that have to be added to the driver circuit are the high voltage diode for the monitoring of the votage between collector and emitter (VCE), because of a possible short-circuit at the IGBT, the current supply for the high voltage side and some difficult-to-integrate passive components and/or elements for optional functions.
In hybrid IGBT control circuits with galvanic separation of the primary side by means of opto-couplers, a fast coupler is used for the signal path, and usually a second, slower coupler to return the error signal.
For the monitoring of the VCE and the supply voltage on the high voltage side (secondary side), integrated components (Motorola Data Sheet MC 33,153) are already available. The secondary, floating voltage supply is realized with a DC/DC converter because of the higher power requirement. The stabilization of the supply voltage is usually made through a longitudinal regulator circuit. For the voltage supply of the secondary side with a DC/DC converter, the three BOTTOM switches of a three-phase-current half-bridge circuit can generally be combined into a voltage supply.
According to the state of the art, the functions of the low-voltage side (as for example signal processing, error processing, current supply) are realized by using discrete elements, or in particular the digital functions are taken over by the controller.
In DE 198 51 186, a circuit arrangement is proposed, where all functions of the primary side for the control, monitoring and current supply of power components (MOSFET or IGBT) are realized in a three-phase bridge circuit for an intermediate power range. This integrated circuit must perform all interface functions between the controller as well as the six drivers and the IGBT switches of the high voltage side. According to the state of the art, opto-couplers (for control signals) are used for the potential separation of the secondary side (high voltage side), and for the driver- and monitoring functions on the secondary side, one circuit is used for each power switch.
In DE 100 14 269.9, a circuit arrangement is proposed, where the level transformation as well as the driver- and monitoring functions of the 3 BOTTOM switches of the respective three IGBT half-bridges as well as an additional seventh switch are combined, so that the result is a monolithically integrated quadruplex gate driver IC. This driver IC for 4 semiconductor switches is on the same potential as the primary control IC and the controller. A common potential of the BOTTOM switches with the control circuit and the controller is possible only under the condition that the interference voltages caused by parasitic effects in the system are relatively small. This is the case in power components for low and intermediate power levels (voltage up to 1200V, current smaller than 150 A per switch) and in three-phase bridge circuit modules of a very compact design, where the internal inductances and resistors can be kept very small. Depending on the switching state, the separate driver stages of the 3 TOP switches of the respective three half bridges can be at the positive intermediate circuit voltage (e.g., 300V . . . 1200V DC). For reasons of isolation, they need to have potential separation (e.g. by means of opto-couplers).
The present invention has the objective to provide a monolithically integrated semiconductor component for a direct gate control and monitoring of a semiconductor switch in a an inverter circuit.
A semiconductor component for the control of a power semiconductor switch in a power inverter, as proposed by the present invention to meet the foregoing objective, has a monolithically integrated circuit arrangement of functional blocks that are operable to perform all of the following functions for the power semiconductor switch:
input interface with Schmitt trigger,
pulse flank memory,
multiple level transformation,
start-up logic with voltage-controlled power on reset,
driver logic,
gate driver for switching-on of the power semiconductor switch,
gate driver for switching-off of the power semiconductor switch,
gate driver for gentle switching-off of the power semiconductor switch,
internal generating and monitoring of an operating voltage and reference voltage,
short-circuit monitoring of the power semiconductor switch by dynamic collector-emitter voltage detection,
error detection/storage and driver for transmission of the error signal to a primary side of the semiconductor component.